Multi Theft Auto (MTA) is an open-source software project that adds full on-line gaming support to Rockstar North's Grand Theft Auto: San Andreas PC game, in which this functionality is not originally found. It is the first open-source modification that adds a highly customizable network play element to a commercial closed-source single-player PC game.
Developed as an experimental piece of software for earlier Grand Theft Auto series, Multi Theft Auto has become an advanced multiplayer platform for gamers and developers. Our software provides on-line gaming for dozens of players running user-generated gameplay content and scripts through a Lua virtual machine, and is freely distributed under the GPLv3 license.

MTA:SA was brillantly developed, allowing any kind of game possibility. From racing to role-playing, forest mazes to hay stack climbings, there are endless possibilities. That makes MTA a modification impossible to get sick of, there's always something new to try out. And everything you need to create your own game is your brain, lua knowledge and a bit of imagination...